| /************************************************************** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| *************************************************************/ |
| |
| import java.awt.Font; |
| import java.awt.Rectangle; |
| import java.awt.Color; |
| import java.awt.Graphics; |
| import javax.swing.JScrollPane; |
| import javax.swing.JTextArea; |
| import javax.swing.JScrollBar; |
| |
| |
| |
| /** A message area displays text in a scrollable text widget. It is a |
| singleton. Other objects can access it directly to display messages. |
| */ |
| public class MessageArea |
| extends JScrollPane |
| { |
| public static synchronized MessageArea Instance () |
| { |
| if (saInstance == null) |
| saInstance = new MessageArea (); |
| return saInstance; |
| } |
| |
| |
| |
| |
| /** Create a new message area. This method is private because the class is |
| a singleton and may therefore not be instanciated from the outside. |
| */ |
| private MessageArea () |
| { |
| maText = new JTextArea(); |
| maText.setBackground (new Color (255,250,240)); |
| maText.setFont (new Font ("Helvetica", Font.PLAIN, 9)); |
| setViewportView (maText); |
| setVerticalScrollBarPolicy (JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); |
| setHorizontalScrollBarPolicy (JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS); |
| |
| printMessage ( |
| "class path is " + System.getProperty ("java.class.path") + "\n"); |
| } |
| |
| |
| |
| |
| /** Show the given string at the end of the message area and scroll to make |
| it visible. |
| */ |
| public static synchronized void print (String aMessage) |
| { |
| print (0, aMessage); |
| } |
| |
| |
| |
| |
| /** Show the given string at the end of the message area and scroll to make |
| it visible. Indent the string as requested. |
| */ |
| public static synchronized void print (int nIndentation, String aMessage) |
| { |
| while (nIndentation-- > 0) |
| aMessage = " " + aMessage; |
| Instance().printMessage(aMessage); |
| } |
| |
| |
| |
| |
| /** Show the given string at the end of the message area and scroll to make |
| it visible. |
| */ |
| public static void println (String aMessage) |
| { |
| println (0, aMessage); |
| } |
| |
| |
| |
| |
| /** Show the given string at the end of the message area and scroll to make |
| it visible. |
| */ |
| public static void println (int nIndentation, String aMessage) |
| { |
| print (nIndentation, aMessage+"\n"); |
| } |
| |
| |
| |
| |
| public void paintComponent (Graphics g) |
| { |
| synchronized (g) |
| { |
| JScrollBar sb = getVerticalScrollBar(); |
| if (sb != null) |
| { |
| int nScrollBarValue = sb.getMaximum() - sb.getVisibleAmount() - 1; |
| sb.setValue (nScrollBarValue); |
| } |
| super.paintComponent (g); |
| } |
| } |
| |
| |
| |
| |
| /** Append the given string to the end of the text and scroll so that it |
| becomes visible. This is an internal method. Use one of the static |
| and public ones. |
| */ |
| private synchronized void printMessage (String aMessage) |
| { |
| maText.append (aMessage); |
| } |
| |
| |
| |
| |
| private static MessageArea saInstance = null; |
| private JTextArea maText; |
| } |